import sys
input = sys.stdin.readline
from collections import *

def judge(x):
    if x%T==0:
        return x-(x-1)//T-V*P<=V
    else:
        return x-x//T-V*P<=V
        
def binary_search():
    l, r = 0, 10**20
    
    while l<=r:
        m = (l+r)//2
        
        if judge(m):
            l = m+1
        else:
            r = m-1
    
    return r

V, T, P = map(int, input().split())
print(binary_search()+1)