#include <fstream>
#define dim 100005
#define LL long long
using namespace std;
 
ifstream f("stergeri.in");
ofstream g("stergeri.out");
 
 
struct cut{
    LL low, high;
};
cut x[dim];
LL N, M, K,sol;
 
 
int main(){
	
    f>>N>>M>>K;
    sol=K;
	
    for (LL i=M;i>=1;--i){
        f>>x[i].low>>x[i].high;
    }
    for (LL i=1; i <= M; ++ i)
        if (sol>=x[i].low){
			
            sol+=x[i].high-x[i].low;
            ++ sol;
        }
    g<<sol;
    return 0;
}