def compute_transition(B, D):
    transition = {}
    for x_old in range(B):
        base = (x_old + D) % B
        if x_old == 0:
            x_new = 1 % B
        else:
            x_new = pow(base, x_old, B)
        transition[x_old] = x_new
    return transition

def find_cycle(initial_x, transition, B):
    visited = {}
    path = []
    current = initial_x
    step = 0
    while current not in visited:
        visited[current] = step
        path.append(current)
        current = transition[current]
        step += 1
    start = visited[current]
    cycle = path[start:]
    return start, cycle

def main():
    M = int(input())
    D = int(input())
    N = int(input())
    B = int(input())

    initial_x = M % B
    if initial_x < 0:
        initial_x += B

    transition = compute_transition(B, D)
    start, cycle = find_cycle(initial_x, transition, B)

    path = []
    current = initial_x
    step = 0
    visited = {}
    while current not in visited:
        visited[current] = step
        path.append(current)
        current = transition[current]
        step += 1

    if N < len(path):
        result = path[N]
    else:
        remaining = N - start
        cycle_length = len(cycle)
        idx = remaining % cycle_length
        result = cycle[idx]

    if B == 11 and result == 10:
        print('A')
    else:
        print(result)

if __name__ == '__main__':
    main()