#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

void push(char C[], int *top, int i) {
	char tmp[3];
	int length;
	sprintf(tmp, "%d", i);
	length = strlen(tmp);
	for (int j = 0; j < length; ++j) {
		C[*top] = tmp[j];
		++*top;
	}
}

int main() {
	char C[101];
	int D, top = 0;
	cin >> D;
	for (int i = 1; i <= 55; ++i) push(C, &top, i);
	cout << C[D - 1];
}