import math

a, b, c = 1, 1, -2

def solve_quadratic(N):
    D = int(math.sqrt(b**2 - 4 * a * c * N))
    n1 = (-b - D) // (2 * a)
    n2 = (-b + D) // (2 * a)
    
    if n1 > 0 and N == n1 * (n1 + 1) // 2:
        return n1
    elif n2 > 0 and N == n2 * (n2 + 1) // 2:
        return n2
    else:
        return -1

def main():
    num_cases = int(input().strip())
    for _ in range(num_cases):
        N = int(input().strip())
        result = solve_quadratic(N)
        print(result)

if __name__ == "__main__":
    main()