用unordered_map求元素出现次数最多的那个，为什么不能全部通过呢？

#include <unordered_map>
using namespace std;

int main(){
    int n, number;
    scanf("%d", &n);
    if (n < 1||n>20)
        return 0;
    unordered_map<int, int> ump;
    for (int i = 0; i <n; i++) {
        scanf("%d", &number);
        ump[number] ++;
    }
    int maxFreq=-1,maxNum=-100000;
    for (unordered_map<int, int>::iterator it = ump.begin(); it != ump.end(); it++) {
        if ((it->second) > maxFreq) {
            maxFreq = it->second;
            maxNum = it->first;
        }
    }
    printf("%d\n",maxNum);
    return 0;
 }