#include <stdio.h>
typedef long long int ll;

ll modPow(ll a,ll p,ll m)
{
    ll res = 1%m;
    while(p>0)
    {
        if(p&1)
            res = (res*a)%m;
        a = (a*a)%m;
        p >>= 1;
    }
    return res;
}
int main()
{
    ll x,a,n,c;
    while(scanf("%lld %lld %lld %lld",&x,&a,&n,&c)==4)
    {
        if(x==0)
            return 0;
        ll mod = modPow(a,n,c);
        ll res = (x*mod)%c;
        ll num = ((1 - mod) % c + c) % c;
        num = (num * a) % c;
        ll modInv = modPow(((1 - a) % c + c) % c, c - 2, c);
        res = ((res - num * modInv) % c + c)%c;
        printf("%lld\n",res);
    }
    return 0;
}