Print the index of interval
if ( tup [ i - 1 ] . Item1 . Item2 < tup [ i ] . Item1 . Item2 ) Console . Write ( tup [ i - 1 ] . Item2 + " ▁ " + tup [ i ] . Item2 ) ; else Console . Write ( tup [ i ] . Item2 + " ▁ " + tup [ i - 1 ] . Item2 ) ; return ; }