var arr= readline().split(" ") for (var i in arr) arr[i] = parseInt(arr[i]) console.log(change(arr)) function change(arr){ var left= 0 var right = arr.length-1 var max = 0 while(left <right){ if(arr[right] - arr[left]> max){ max = arr[right] - arr[left] } if(arr[left]-arr[left+1] > arr[right-1] - arr[right]){ left++ } else right -- } return max }