rt，题目传送门

# include <bits/stdc++.h>
using namespace std;

int n, m;
int a;
int arr[1000005][2];
int ans = 0;

int main (void){
	
	scanf ("%d %d", &n, &m);
	
	for (int i = 0;i < n;i++){
		for (int j = 0;j < m;j++){
			scanf ("%d %d", &arr[i][0], &arr[i][1]);
		}
	}
	
	scanf ("%d", &a);
	
	int temp = a;
	for (int i = 0;i < n;i++){
		for (int j = temp;;j++){
			if (j == m){
				j = 0;
			}
			if (arr[j][0] == 1){
				temp = j;
				ans += arr[j][1];
				break;
			}
		}
	}
	
	printf ("%d", ans);
	
	return 0;
}