#include <stdio.h>
#include <string.h>

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

int main(void)
{
	char C[101];
	int D, top = 0, i;
	scanf("%d", &D);
	for (i = 1; i <= 55; ++i) push(C, &top, i);
	printf("%c", C[D - 1]);
	return 0;
}