from sys import stdin

import sys



A, B, N = [int(x) for x in stdin.readline().rstrip().split()]

# N, M = [int(x) for x in stdin.readline().rstrip().split()]

# U = input().split()

x=min(B-1,N)

ans = int((A*x)/B)-A*int(x/B)

print(ans)

# if N >= B:
from sys import stdin

import sys

 

A, B, N = [int(x) for x in stdin.readline().rstrip().split()]

# N, M = [int(x) for x in stdin.readline().rstrip().split()]

# U = input().split()

ans = int((A*N)/B)-A*int(N/B)

ans2=0

if B-1<N:

	ans = int((A*(B-1))/B)-A*int((B-1)/B)

else:

  	ans2=0

    

 

 

print(ans)
from sys import stdin
import sys

A, B, N = [int(x) for x in stdin.readline().rstrip().split()]
# N, M = [int(x) for x in stdin.readline().rstrip().split()]
# U = input().split()
x = min(B - 1, N)
ans = int((A * x) / B) - A * int(x / B)
print(ans)
# if N >= B:

from sys import stdin
import sys

A, B, N = [int(x) for x in stdin.readline().rstrip().split()]
# N, M = [int(x) for x in stdin.readline().rstrip().split()]
# U = input().split()
ans = int((A * N) / B) - A * int(N / B)
ans2 = 0
if B - 1 < N:
    ans = int((A * (B - 1)) / B) - A * int((B - 1) / B)
else:
    ans2 = 0
print(ans)

-x = min(B - 1, N) -ans = int((A * x) / B) - A * int(x / B) +ans = int((A * N) / B) - A * int(N / B) +ans2 = 0 +if B - 1 < N: +    ans = int((A * (B - 1)) / B) - A * int((B - 1) / B) +else: +    ans2 = 0 -# if N >= B: