90求帮

#include <iostream>
using namespace std;

int main()
{
    int n,y,s,t;
    cin>>n>>y>>s>>t;
    int time1 = 0,time2 = 0;
    for (int i = 0;i<n;i++)
    {
        time1 = i*s+y;
        time2 = (i+1)*s+y;
        if ((time1 % t != 0) and (time2 % t != 0))
        {
            cout<<"Yes"<<endl;
            break;
        }
        else
        {
            if (i+1 == n)
            {
                cout<<"No"<<endl;
                break;
            }
        }
    }
    return 0;
}