#include <stdio.h>
int findHighestAltitude(int arr[], int n){
    int max = arr[0];
    int j;
    for (j = 1; j < n; j++){
        if (arr[j] > max){
            max = arr[j];
        }
    }
    return max;
}
int main(){
    int n;
    if (scanf("%d", &n) != 1) return 0;
    if (n < 0 || n > 10){
        printf("Invalid input");
        return 0;
    }
     if (n == 0){
        printf("Invalid input");
        return 0;
    }
    int altitude[10];
    int i;
    for (i = 0; i < n; i++){
        if (scanf("%d", &altitude[i]) != 1){
            printf("Invalid input");
            return 0;
        if (altitude[i] < -100 || altitude[i] > 100){
            printf("Invalid input");
            return 0;
        }
    }
   
    int highest = findHighestAltitude(altitude, n);
    printf("%d", highest);
    return 0;
}