#include <stdio.h>

int main() {
    int a, b, c, d;

    scanf("%d", &a);
    scanf("%d", &b);
    scanf("%d", &c);
    scanf("%d", &d);

    if (c - d >= a && c - d <= b) {
        printf("S\n");
    } else {
        printf("N\n");
    }
    
    return 0;
}