#include <cstdio>
#include <stack>
using namespace std;

stack < int  > X;
stack < int  > Y;

int main()
{

    freopen("stergeri.in","r",stdin);
    freopen("stergeri.out","w",stdout);

    int n, i, j, s, t, d, k, x, y;

    scanf("%d%d%d",&n,&d,&k);
    for( i = 1; i <= d; ++i ){
        scanf("%d%d",&x,&y);
        X.push(x);
        Y.push(y);
    }

    while( !X.empty() ){
        if( X.top() <= k )
            k += Y.top() - X.top() + 1;
        X.pop();
        Y.pop();
    }

    printf("%d",k);


    return 0;
}