// editor3
#include<stdio.h>
#define MAX 12 
int main(){
    int K;
    if (scanf("%d", &K) != 1 || K<4 || K>12){
        printf("Invalid input");
        return 0;
        
    }
    int pulses[K];
    for (int i=0; i<K;i++){
        if (scanf("%d",&pulses[i]) != 1 || pulses[i]<1 || pulses[i] > 5000){
            printf("Invalid input");
            return 0;
        }
    }
    int accepted[K],count=0;
    int sum=0;
    for(int i=0; i<K;i++ ){
        if (pulses[i] > sum){
        accepted[count++]=pulses[i];
        sum+=pulses[i];
    }
    }
    if (count ==0){
        printf("Invalid input")
        return 0;
    }
    int min = accepted[0],max=accepted[0];
    for (int i=1;i < count;i++){
        if (accepted[i] < min)min=accepted[i];
        printf("%d",max - min);
        return 0;
    }
}