#include <stdio.h>
int main(void){
    int i, n;
    char data[6];
    scanf( "%d", &n );
    data[0] = '1';
    data[1] = '4';
    data[2] = '2';
    data[3] = '8';
    data[4] = '5';
    data[5] = '7';
    if( n > 0 ){
        printf( "0." );
        for( i = 0; i < n; i++ ){
            printf( "%c", data[(i%6)] );
        }
    }else{
        printf( "0" );
    }
    printf( "\n" );
}