## TSUM - Triple Sums

You're given a sequence **s** of **N** distinct integers.

Consider all the possible sums of three integers from the sequence at three different indices.

For each obtainable sum output the number of different triples of indices that generate it.

Constraints:

N <= 40000, |s_{i}| <= 20000

### Input

The first line of input contains a single integer N.

Each of the next N lines contain an element of s.

### Output

Print the solution for each possible sum in the following format:

sum_value : number_of_triples

Smaller sum values should be printed first.

### Example

Input:

5

-1

2

3

0

5

Output:1 : 1

2 : 1

4 : 2

5 : 1

6 : 1

7 : 2

8 : 1

10 : 1

**Explanation:**

4 can be obtained using triples ( 0, 1, 2 ) and ( 0, 3, 4 ).

7 can be obtained using triples ( 0, 2, 4 ) and ( 1, 3, 4 ).**Note:** a triple is considered the same as any of its permutations.

hide comments

manuelloaiza:
2021-03-04 05:07:52
Nice problem. Try to create your own Complex struct instead of using complex<long double> to avoid TLE. |

Added by: | gustav |

Date: | 2011-02-18 |

Time limit: | 1s |

Source limit: | 50000B |

Memory limit: | 1536MB |

Cluster: | Cube (Intel G860) |

Languages: | All except: ASM64 |

Resource: | own problem, used for a contest on codechef |