#include <cstdio>

const int Nmax = 100005;

int N, M, K;
int A[Nmax], B[Nmax];

void ReadData() {
	freopen("stergeri.in", "r", stdin);
	freopen("stergeri.out", "w", stdout);
	
	scanf("%d %d %d", &N, &M, &K);
	for (int i = 1; i <= M; ++i)
		scanf("%d %d", A+i, B+i);
}

void Solve() {
	for (int i = M; i; --i)
		if (A[i] <= K)
			K += B[i]-A[i]+1;
	printf("%d\n", K);
}

int main() {
	ReadData();
	Solve();
}