Wrong Answer-Egyption Fractions problem

general
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1

I have been trying this problem for some days.The problem is

My solution is CodeChef: Practical coding for everyone.

Approach:

For a fraction a/b, the largest fraction which can be subtracted is 1/ceil(b/a).(Greedy approach)

k=ceil(b/a)

The new fraction a’/b’=(kXa-b)/(kXb)

Am I wrong with this approach?

2

Looks like long long is not going to suffice. The range of inputs is way too large it seems from the solutions. No where are the constraints mentioned.

3

yes…the range is exceeding 10^18 in this question…

4

In the comments below the question(originally from ICPC Kanpur online round),constraints mentioned were for a,b<=1000