func lonelyinteger(a []int32) int32 {
    // Write your code here
    // var r int32 = 0
    // for _, a := range a{
    //     r ^= a
    // }
    // return r
    var result int32 = 0
    m := make(map[int32]int32)
    for _, v :=range a{
        value, exists := m[v]
        if exists{
            m[v] = value+1
            // fmt.Printf("Exist: key= %d, not= %d", v, value+1)
        }else{
            m[v] = 1
            // fmt.Printf("Newone: key= %d, not= %d", v, 1)
        }
    }
    for key, value := range m{
        if value == 1{
            result = key
        }
    }
    return result
}