Problem:
Score : 100 points

Problem Statement

There are N children in AtCoder Kindergarten. Mr. Evi will arrange the children in a line, then give 1 candy to the first child in the line, 2 candies to the second child, ..., N candies to the N-th child. How many candies will be necessary in total?

Constraints

1≦N≦100

Input

The input is given from Standard Input in the following format:

N

Output

Print the necessary number of candies in total.

Sample Input 1

3

Sample Output 1

6

The answer is 1+2+3=6.

Sample Input 2

10

Sample Output 2

55

The sum of the integers from 1 to 10 is 55.

Sample Input 3

1

Sample Output 3

1

Only one child. The answer is 1 in this case.

Solution in Julia (0.5.0) (judge verdict: Accepted)

MyString=Union{String,SubString{String},Char}
MyStringArray=Union{Array{String,1},Array{SubString{String},1},Array{Char,1}}
parseInt(x::MyString) = parse(Int, x)
parseInt(x::Real) = trunc(Int, x)
parseBigInt(x::MyString) = parse(BigInt, x)
parseBigInt(x::Real) = trunc(BigInt, x)
parseFloat(x::MyString) = parse(Float64, x)
parseFloat(x::Real) = trunc(Float64, x)
parseBigFloat(x::MyString) = parse(BigFloat, x)
parseBigFloat(x::Real) = trunc(BigFloat, x)
parseMap(x::MyStringArray) = map(parseInt, x)
parseMapBig(x::MyStringArray) = map(parseBigInt, x)

function main()
    n=parseInt(readline())
    println(sum([i for i in 1:n]))
end
main()