#include<stdio.h>
#include<limits.>
int main(){
    int n, num, min_val = INT_MAX;
    int invalid_input = 0;
    scanf("%d", &n);
    for(int i = 0; i < n; i++){
        scanf("%d", &num);
        if(num < 0){
            invalid_input = 1;
        }
        if(num >= 0 && num < min_val){
            min_val = num;
        }
    }
    if(invalid_input){
        printf("Invalid Input\n");
    }else{
        printf("%d\n", min_val);
    }
    return 0;
}