#include<iostream>
using namespace std;

typedef unsigned long long ULL;

ULL ANS(ULL a,ULL b,ULL p){

    a%=p;b%=p;
    ULL c = (long double)a*b/p;
    //cout<<a<<b<<endl;
    ULL x = a*b-p,y = c*p-p;
    //cout<<x<<" "<<y<<endl;
    long long ans = (long long)(x%p) - (long long)(y%p);

    if(ans<0) ans+=p;
    return ans;
}

int main(){
    ULL a,b,p;
    scanf("%llu%llu%llu",&a,&b,&p);

    cout<<ANS(a,b,p)<<endl;
    return 0;

}