// editor3
#include<stdio.h>
int mian()
{
    int k;
    if(scanf("%d",&k)!=1)
    {
        printf("Invalid input\n");
        return 0;
    }
    if(k<4||k>12)
    {
        printf("Invalid input\n");
        return 0;
    }
    int pulses[k];
    for (int i=0;i<k;i++)
    {
        if(scanf("%d",&pulses[i])!=1)
        {
            printf("Invalid input\n");
            return 0;
        }
    }
    int stored[k],storedCount=0;
    int total=0;
    for (int i=0;i<k;i++)
    {
        if(pulses[i]>total)
        {
            stored[storedCount++]=pulses[i];
            total+=pulses[i];
        }
    }
    if(storedCount==0)
    {
        printf("0\n");
        return 0;
    }
    int max=stored[0],min=stored[0];
    for(int i=1;i<storedCount;i++)
    {
        if(stored[i]>max)max=stored[i];
        if(stored[i]<min)min=stored[i];
    }
    printf("%d\n",max-min);
    return 0;
}