#include<stdio.h>
#include<string.h>
#include<ctype.h>
int main(){
    int n, max = 1001;
    char s[20];
    scanf("%d", &n);
    for(int i = 0; i < n; i++){
        scanf("%s",s);
        for(int j=0;j<strlen&s;j++) {
            if(! isdigit(s[j])&&s[j]i='-'){
                printf("Invalid input");
                return 0;
            }
        }
        int val;
        scanf(s,"%d", &val);
        int(val > max)
        max = val;
    }
    printf("%d ", max);
    return 0;
}