int max_of_four(int a, int b, int c, int d) {
    int nums[] = {a, b, c, d};
    int mx = nums[0]; 
    
    for (int i = 1; i < 4; i++) {
        if(nums[i] > mx) {
            mx = nums[i]; 
        }        
    }   
    return mx; 
}
int main() {
    int a, b, c, d;
    scanf("%d %d %d %d", &a, &b, &c, &d);
    int ans = max_of_four(a, b, c, d);
    printf("%d", ans);
    
    return 0;
}