A, B, N = list(map(int, input().split()))

from fractions import gcd



ans = 0



x = min(B-1, N)

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



ans = p



print(ans)
import sys

def input(): return sys.stdin.readline().strip()

def mapint(): return list(map(int, input().split()))

sys.setrecursionlimit(10**9)



A, B, N = mapint()

x = min(B-1, N)

print((int(A*x/B)-A*int(x/B)))
A, B, N = list(map(int, input().split()))
from fractions import gcd

ans = 0
x = min(B - 1, N)
p = int((A * x) / B) - A * int(x / B)
ans = p
print(ans)

import sys


def input():
    return sys.stdin.readline().strip()


def mapint():
    return list(map(int, input().split()))


sys.setrecursionlimit(10**9)
A, B, N = mapint()
x = min(B - 1, N)
print((int(A * x / B) - A * int(x / B)))

-A, B, N = list(map(int, input().split())) -from fractions import gcd +import sys -ans = 0 + +def input(): +    return sys.stdin.readline().strip() + + +def mapint(): +    return list(map(int, input().split())) + + +sys.setrecursionlimit(10**9) +A, B, N = mapint() -p = int((A * x) / B) - A * int(x / B) -ans = p -print(ans) +print((int(A * x / B) - A * int(x / B)))