You are playing another computer game, and now you have to slay n monsters. These monsters are standing in a circle, numbered clockwise from 1 to n. Initially, the i-th monster has a_i health.

You may shoot the monsters to kill them. Each shot requires exactly one bullet and decreases the health of the targeted monster by 1 (deals 1 damage to it). Furthermore, when the health of some monster i becomes 0 or less than 0, it dies and explodes, dealing b_i damage to the next monster (monster i + 1, if i < n, or monster 1, if i = n). If the next monster is already dead, then nothing happens. If the explosion kills the next monster, it explodes too, damaging the monster after it and possibly triggering another explosion, and so on.

You have to calculate the minimum number of bullets you have to fire to kill all n monsters in the circle.

Input

The first line contains one integer T (1 ≤ T ≤ 150000) — the number of test cases.

Then the test cases follow, each test case begins with a line containing one integer n (2 ≤ n ≤ 300000) — the number of monsters. Then n lines follow, each containing two integers a_i and b_i (1 ≤ a_i, b_i ≤ 10^{12}) — the parameters of the i-th monster in the circle.

It is guaranteed that the total number of monsters in all test cases does not exceed 300000.

Output

For each test case, print one integer — the minimum number of bullets you have to fire to kill all of the monsters.

Example

Input


1
3
7 15
2 14
5 3


Output


6
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.List;
import java.util.Set;

public class C {

    class Pair {
        long ai, bi;

        public Pair(long ai, long bi) {
            this.ai = ai;
            this.bi = bi;
        }
    }

    public void solve() {
        InputReader in = new InputReader(System.in);
        OutputWriter out = new OutputWriter(System.out);
        int t = in.readInt();

        while (t-- > 0) {
            int n = in.readInt();
            ArrayList<Pair> monsters = new ArrayList<>();
            long minBullets[] = new long[n];
            long res = 0;
            long minAi = Long.MAX_VALUE;
            for (int i = 0; i < n; i++) {
                long ai = in.readLong(), bi = in.readLong();
                monsters.add(new Pair(ai, bi));
                if ( i > 0 ) {
                    minBullets[i] = Math.max(ai - monsters.get(i - 1).bi, 0);
                    res+=minBullets[i];
                    minAi = Math.min(minAi, ai-minBullets[i]);
                }
                if ( i == n - 1 ) {
                    minBullets[0] = Math.max(monsters.get(0).ai - bi, 0);
                    res+=minBullets[0];
                    minAi = Math.min(minAi, monsters.get(0).ai-minBullets[0]);
                }
            }
            out.printLine(res+minAi);
            out.flush();
        }
    }

    public static void main(String[] args) {
        C solver = new C();
        solver.solve();
    }

    static class InputReader {

        private InputStream stream;
        private byte[] buf = new byte[1024];
        private int curChar;
        private int numChars;
        private SpaceCharFilter filter;

        public InputReader(InputStream stream) {
            this.stream = stream;
        }

        public int read() {
            if ( numChars == -1 )
                throw new InputMismatchException();
            if ( curChar >= numChars ) {
                curChar = 0;
                try {
                    numChars = stream.read(buf);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if ( numChars <= 0 )
                    return -1;
            }
            return buf[curChar++];
        }

        public int readInt() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if ( c == '-' ) {
                sgn = -1;
                c = read();
            }
            int res = 0;
            do {
                if ( c < '0' || c > '9' )
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public long readLong() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            int sgn = 1;
            if ( c == '-' ) {
                sgn = -1;
                c = read();
            }
            long res = 0;
            do {
                if ( c < '0' || c > '9' )
                    throw new InputMismatchException();
                res *= 10;
                res += c - '0';
                c = read();
            } while (!isSpaceChar(c));
            return res * sgn;
        }

        public String readString() {
            int c = read();
            while (isSpaceChar(c))
                c = read();
            StringBuilder res = new StringBuilder();
            do {
                res.appendCodePoint(c);
                c = read();
            } while (!isSpaceChar(c));
            return res.toString();
        }

        public boolean isSpaceChar(int c) {
            if ( filter != null )
                return filter.isSpaceChar(c);
            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }

        public String next() {
            return readString();
        }

        public interface SpaceCharFilter {
            public boolean isSpaceChar(int ch);
        }
    }

    static class OutputWriter {
        private final PrintWriter writer;

        public OutputWriter(OutputStream outputStream) {
            writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
        }

        public OutputWriter(Writer writer) {
            this.writer = new PrintWriter(writer);
        }

        public void print(Object... objects) {
            for (int i = 0; i < objects.length; i++) {
                if ( i != 0 )
                    writer.print(' ');
                writer.print(objects[i]);
            }
        }

        public void printLine(Object... objects) {
            print(objects);
            writer.println();
        }

        public void close() {
            writer.close();
        }

        public void flush() {
            writer.flush();
        }

    }

    static class IOUtils {

        public static int[] readIntegerArray(InputReader in, int size) {
            int[] array = new int[size];
            for (int i = 0; i < size; i++) {
                array[i] = in.readInt();
            }
            return array;
        }

        public static long[] readLongArray(InputReader in, int size) {
            long[] array = new long[size];
            for (int i = 0; i < size; i++) {
                array[i] = in.readLong();
            }
            return array;
        }

        public static List<Integer> readIntegerList(InputReader in, int size) {
            List<Integer> set = new ArrayList<>();
            for (int i = 0; i < size; i++) {
                set.add(in.readInt());
            }
            return set;
        }

        public static Set<Integer> readIntegerSet(InputReader in, int size) {
            Set<Integer> set = new HashSet<Integer>();
            for (int i = 0; i < size; i++) {
                set.add(in.readInt());
            }
            return set;
        }
    }
}