Wilbur the pig is tinkering with arrays again. He has the array a1, a2, ..., an initially consisting of n zeros. At one step, he can choose any index i and either add 1 to all elements ai, ai + 1, ... , an or subtract 1 from all elements ai, ai + 1, ..., an. His goal is to end up with the array b1, b2, ..., bn. 

Of course, Wilbur wants to achieve this goal in the minimum number of steps and asks you to compute this value.

Input

The first line of the input contains a single integer n (1 ≤ n ≤ 200 000) — the length of the array ai. Initially ai = 0 for every position i, so this array is not given in the input.

The second line of the input contains n integers b1, b2, ..., bn ( - 109 ≤ bi ≤ 109).

Output

Print the minimum number of steps that Wilbur needs to make in order to achieve ai = bi for all i.

Examples

Input

5
1 2 3 4 5


Output

5

Input

4
1 2 2 1


Output

3

Note

In the first sample, Wilbur may successively choose indices 1, 2, 3, 4, and 5, and add 1 to corresponding suffixes.

In the second sample, Wilbur first chooses indices 1 and 2 and adds 1 to corresponding suffixes, then he chooses index 4 and subtract 1.
	import java.io.*;
	import java.math.*;
	import java.nio.file.attribute.AclEntry.Builder;
	import java.security.KeyStore.Entry;
	import java.util.*;
	 
	 
	public   class CODEFORCES {
		private InputStream is;
		private PrintWriter out;
		int time = 0, dp[][], DP[], start[], end[], dist[],  black[], MOD = (int)(1e9+7), arr[], weight[][];
		int MAX = 800000, N, K, L;
		long red[];
		ArrayList<Pair>[] amp;
		boolean b[], boo[][];
		Pair prr[], parent[][];
		HashSet<Integer> hs = new HashSet<>();
		
	 
		public static void main(String[] args) throws Exception {
			new Thread(null, new Runnable() {
			public void run() {
				try {
	 
			//new Main().soln();
			} catch (Exception e) {
					System.out.println(e);
				}
			}
		}, "1", 1 << 26).start();
			new CODEFORCES().soln();
		}
		char ch[][];
		int ans = 0;
		void solve() {
			int n = ni();
			int arr[] = na(n);
			long ans = 0, val = 0;
			for(int i = 0; i < n; i++){
				ans += Math.abs(val-arr[i]);
				val = arr[i];
			}
			System.out.println(ans);
		}
		public void dfs(int x, long temp){
			b[x] = true;
			if(x!=0){
				if(temp>arr[x]) {ans+=red[x];return;}
			}
			long g = Math.max(0, temp);
			for(Pair p : amp[x]){
				int u = p.u, v = p.v;
				if(!b[u]){
					dfs(u,g+v);
				}
			}
		}
		public long dfs(int x){
			b[x] = true;
			for(Pair p : amp[x]){
				if(!b[p.u]) red[x]+=dfs(p.u);
			}
			return (++red[x]);
		}
		public static class FenwickTree {
			
		    int[] array; // 1-indexed array, In this array We save cumulative information to perform efficient range queries and updates
	 
		    public FenwickTree(int size) {
		        array = new int[size + 1];
		    }
		    public int rsq(int ind) {
		        assert ind > 0;
		        int sum = 0;
		        while (ind > 0) {
		            sum += array[ind];
		            //Extracting the portion up to the first significant one of the binary representation of 'ind' and decrementing ind by that number
		            ind -= ind & (-ind);
		        }
		        return sum;
		    }
		    public int rsq(int a, int b) {
		        assert b >= a && a > 0 && b > 0;
		        return rsq(b) - rsq(a - 1);
		    }
		    public void update(int ind, int value) {
		        assert ind > 0;
		        while (ind < array.length) {
		            array[ind] += value;
		            //Extracting the portion up to the first significant one of the binary representation of 'ind' and incrementing ind by that number
		            ind += ind & (-ind);
		        }
		    }
		    public int size() {
		        return array.length - 1;
		    }
		}
		void buildGraph(int n){
			for(int i = 0; i<n ;i++){
				int x = ni() -1, y = ni();
				amp[i+1].add(new Pair(x,y));
				amp[x].add(new Pair(i+1,y));
			}
		}
		long get(int x){
			long val = 0;
			for(int i = 0; i< N; i++){
				val += Math.abs(x-arr[i]);
				x+=L;
			}
			return val;
		}
		void dfs(int i, int j){
			boo[i][j] = true;
			if(ch[i][j]=='F') return;
			Pair p = new Pair(i,j);
			if(i>0 && ch[i-1][j]!='*' && !boo[i-1][j]){
				parent[i-1][j] = p;
				dfs(i-1,j);
			}
			if(j>0 && ch[i][j-1]!='*' && !boo[i][j-1]){
				parent[i][j-1] = p;
				dfs(i,j-1);
			}
			if(i<N-1 && ch[i+1][j]!='*' && !boo[i+1][j]){
				parent[i+1][j] = p;
				dfs(i+1,j);
			}
			if(j<K-1 && ch[i][j+1]!='*' && !boo[i][j+1]){
				parent[i][j+1] = p;
				dfs(i,j+1);
			}
		}
		void recur(int n, int k){
			if(k<0) return;
			hs.add(K-k);
			if(n>=0 && dp[n][k]!=-1) return;
			if(n>=0) dp[n][k] = 1;
			for(int i = n+1;i<N;i++){
				recur(i,k-arr[i]);
			}
		}
		long modInverse(long a, long mOD2){
	        return  power(a, mOD2-2, mOD2);
		}
		long power(long x, long y, long m)
		{
			if (y == 0)
	    return 1;
		long p = power(x, y/2, m) % m;
		p = (p * p) % m;
	 
		return (y%2 == 0)? p : (x * p) % m;
		}
		boolean isPrime(int x){
			for(int i = 2;i*1L*i<=x;i++) if(x%i==0) return false;
			return true;
		}
		public String isPossible(int b[]){
			String ans = "Possible";
			int n = b.length;
			Arrays.sort(b);
			if(n==1) return "Possible";
			if(b[0]==1) return "Impossible";
			if(b[0]>=n) return ans;
			int lcm = 1;
			for(int i : b){
				long gcd = gcd(lcm,i);
				lcm *= (i/gcd);
			}
			int cnt = 0;
			for(int i : b) cnt+=lcm/i;
			if(cnt>lcm) return "Impossible";
			return ans;
		}
		public long gcd(long a, long b){
			if(b==0) return a;
			return gcd(b,a%b);
		}
		void failFn(String str, int arr[]){
			int len = 0;
			arr[0] = 0;
			int i = 1;
			while(i<arr.length){
				if(str.charAt(i)==str.charAt(len)){
					arr[i++] = ++len;
					continue;
				}
				if(len == 0){
					arr[i] = len;
					i++;
					continue;
				}
				if(str.charAt(i)!=str.charAt(len)){
					len = arr[len-1];
				}
			}
		}
		static class ST1{
			int arr[], st[], size;
			ST1(int a[]){
				arr = a.clone();
				size = 10*arr.length;
				st = new int[size];
				build(0,arr.length-1,1);
			}
			void build(int ss, int se, int si){
				if(ss==se){
					st[si] = arr[ss];
					return;
				}
				int mid = (ss+se)/2;
				int val = 2*si;
				build(ss,mid,val); build(mid+1,se,val+1);
				st[si] = Math.min(st[val], st[val+1]);
			}
			int get(int ss, int se, int l, int r, int si){
				if(l>se || r<ss || l>r) return Integer.MAX_VALUE;
				if(l<=ss && r>=se) return st[si];
				int mid = (ss+se)/2;
				int val = 2*si;
				return Math.min(get(ss,mid,l,r,val), get(mid+1,se,l,r,val+1));
			}
		}
		static class ST{
			int arr[],lazy[],n;
			ST(int a){
				n = a;
				arr = new int[10*n];
				lazy = new int[10*n];
			}
			void up(int l,int r,int val){
				update(0,n-1,0,l,r,val);
			}
			void update(int l,int r,int c,int x,int y,int val){
				if(lazy[c]!=0){
					lazy[2*c+1]+=lazy[c];
					lazy[2*c+2]+=lazy[c];
					if(l==r)
						arr[c]+=lazy[c];
					lazy[c] = 0;
				}
				if(l>r||x>y||l>y||x>r)
					return;
				if(x<=l&&y>=r){
					lazy[c]+=val;
					return ;
				}
				int mid = l+r>>1;
				update(l,mid,2*c+1,x,y,val);
				update(mid+1,r,2*c+2,x,y,val);
				arr[c] = Math.max(arr[2*c+1], arr[2*c+2]);
			}
			int an(int ind){
				return ans(0,n-1,0,ind);
			}
			int ans(int l,int r,int c,int ind){
				if(lazy[c]!=0){
					lazy[2*c+1]+=lazy[c];
					lazy[2*c+2]+=lazy[c];
					if(l==r)
						arr[c]+=lazy[c];
					lazy[c] = 0;
				}
				if(l==r)
					return arr[c];
				int mid = l+r>>1;
				if(mid>=ind)
					return ans(l,mid,2*c+1,ind);
				return ans(mid+1,r,2*c+2,ind);
			}
		}
		
		public static int[] shuffle(int[] a, Random gen){
			for(int i = 0, n = a.length;i < n;i++)
			{ 
				int ind = gen.nextInt(n-i)+i; 
				int d = a[i]; 
				a[i] = a[ind];
				a[ind] = d; 
			} 
		return a; 
		}
	 
		class Pair implements Comparable<Pair>{
			int u, v, i;
			Pair(int u, int v){
				this.u = u;
				this.v = v;
			}
			Pair(int u, int v, int i){
				this.u = u;
				this.v = v;
				this.i = i;
			}
			public int hashCode() {
				return Objects.hash();
			}
			/*public boolean equals(Object o) {
				Pair other = (Pair) o;
				return ((u == other.u && v == other.v) || (v == other.u && u == other.v));
			}*/
			public int compareTo(Pair other) {
				//return Integer.compare(val, other.val);
				return Long.compare(u, other.u) != 0 ? (Long.compare(u, other.u)) : (Long.compare(v,other.v));
			}
			public String toString(){
				return this.u +" " + this.v;
			}
		}
		long power(long x, long y, int mod){
			long ans = 1;
			while(y>0){
				if(y%2==0){
					x = (x*x)%mod;
					y/=2;
				}
				else{
					ans = (x*ans)%mod;
					y--;
				}
			}
			return ans;
		}
		void soln() {
			is = System.in;
			out = new PrintWriter(System.out);
			long s = System.currentTimeMillis();
			solve();
			//out.close();
			out.flush();
			//tr(System.currentTimeMillis() - s + "ms");
		}
	 
	 
		// To Get Input
		// Some Buffer Methods
		private byte[] inbuf = new byte[1024];
		public int lenbuf = 0, ptrbuf = 0;
	 
		private int readByte() {
			if (lenbuf == -1)
				throw new InputMismatchException();
			if (ptrbuf >= lenbuf) {
				ptrbuf = 0;
				try {
					lenbuf = is.read(inbuf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (lenbuf <= 0)
					return -1;
			}
			return inbuf[ptrbuf++];
		}
	 
		private boolean isSpaceChar(int c) {
			return !(c >= 33 && c <= 126);
		}
	 
		private int skip() {
			int b;
			while ((b = readByte()) != -1 && isSpaceChar(b))
				;
			return b;
		}
	 
		private double nd() {
			return Double.parseDouble(ns());
		}
	 
		private char nc() {
			return (char) skip();
		}
		private String ns() {
			int b = skip();
			StringBuilder sb = new StringBuilder();
			while (!(isSpaceChar(b))) { // when nextLine, (isSpaceChar(b) && b != '
										// ')
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}
	 
		private char[] ns(int n) {
			char[] buf = new char[n];
			int b = skip(), p = 0;
			while (p < n && !(isSpaceChar(b))) {
				buf[p++] = (char) b;
				b = readByte();
			}
			return n == p ? buf : Arrays.copyOf(buf, p);
		}
	 
		private char[][] nm(int n, int m) {
			char[][] map = new char[n][];
			for (int i = 0; i < n; i++)
				map[i] = ns(m);
			return map;
		}
	 
		private int[] na(int n) {
			int[] a = new int[n];
			for (int i = 0; i < n; i++)
				a[i] = ni();
			return a;
		}
	 
		private int ni() {
			int num = 0, b;
			boolean minus = false;
			while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
				;
			if (b == '-') {
				minus = true;
				b = readByte();
			}
	 
			while (true) {
				if (b >= '0' && b <= '9') {
					num = num * 10 + (b - '0');
				} else {
					return minus ? -num : num;
				}
				b = readByte();
			}
		}
	 
		private long nl() {
			long num = 0;
			int b;
			boolean minus = false;
			while ((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'))
				;
			if (b == '-') {
				minus = true;
				b = readByte();
			}
	 
			while (true) {
				if (b >= '0' && b <= '9') {
					num = num * 10 + (b - '0');
				} else {
					return minus ? -num : num;
				}
				b = readByte();
			}
		}
	 
		private boolean oj = System.getProperty("ONLINE_JUDGE") != null;
	 
		private void tr(Object... o) {
			if (!oj)
				System.out.println(Arrays.deepToString(o));
		}
	} 