a, b, n = list(map(int, input().split()))



x = min(b - 1, n)

ans = int(a * x / b)



#if a == 1 or b == 1 or b == n:

#    print(0)

#else:

print(ans)

a, b, n = list(map(int, input().split()))



x = min(b - 1, n)

print((int(a * x / b)))

a, b, n = list(map(int, input().split()))
x = min(b - 1, n)
ans = int(a * x / b)
# if a == 1 or b == 1 or b == n:
#    print(0)
# else:
print(ans)

a, b, n = list(map(int, input().split()))
x = min(b - 1, n)
print((int(a * x / b)))

-ans = int(a * x / b) -# if a == 1 or b == 1 or b == n: -#    print(0) -# else: -print(ans) +print((int(a * x / b)))