#include <stdio.h> int Geam(int x, int y)//比较大小的函数 { if (x > y) return x; else return y; } int main() { int a, b, c, d; scanf("%d %d %d %d",&a, &b, &c, &d); int i = Geam(a, b); int j = Geam(c, d); int e = Geam(i, j); printf("%d", e); return 0; }