// editor4
#include<stdio.h>
#include<string.h>
#include<ctype.h>
struct Student {
    int id;
    char name[50];
};
int isNumber(char str[]){
    for(int i = 0; str[i]; i++){
        if (!isdigit(str[i]))
        return 0;
    }
    return 1;
}
int main(){
    int n;
    scanf("%d", &n);
    struct Student s[1000];
    for(int i = 0; i < n; i++){
        char idstr[20];
        scanf("%s", idstr);
        if(!isNumber(idstr)){
            printf("Invalid input\n");
            return 0;
        }
        s[i].id = atoi(idstr);
        scanf("%s", s[i].name);
    }
    char searchStr[20];
    scanf("%s", searchStr);
    if (!isNumber(searchStr)){
        printf("Invalid input\n");
        return 0;
    }
    int searchId = atoi(searchStr);
    int found = 0;
    for(int i = 0; i < n; i++){
        if (s[i].id == searchId){
            printf("%S\n", s[i].name);
            found = 1;
            break;
        }
    }
    if(!found)
    printf("Student ID not found\n");
    return 0;

}