import sys

def compute_case1(d, H1, H2, H3):
    min_steps = float('inf')
    max_k2 = 100
    for k2 in range(0, max_k2 + 1):
        h2 = H2 - k2 * d
        if h2 < 0:
            break
        # Compute k1 for H1 < h2
        if H1 >= h2:
            required_h1 = h2 - 1
            if required_h1 < 0:
                # H1 can't be reduced to <0 and >=0, but required_h1 is -1, so H1' must be 0, which is <h2 only if h2>0
                if h2 == 0:
                    continue  # H1' is 0, which is not <0
                else:
                    # H1 needs to be reduced to 0
                    k1 = (H1 + d - 1) // d  # ceil division to reach <=0
                    h1 = 0
                    if h1 >= h2:
                        continue
            else:
                k1 = (H1 - required_h1 + d - 1) // d
                h1 = H1 - k1 * d
                if h1 < 0:
                    h1 = 0
                if h1 >= h2:
                    continue
        else:
            k1 = 0
            h1 = H1
        # Compute k3 for H3 < h2
        if H3 >= h2:
            required_h3 = h2 - 1
            if required_h3 < 0:
                if h2 == 0:
                    continue
                else:
                    k3 = (H3 + d - 1) // d
                    h3 = 0
                    if h3 >= h2:
                        continue
            else:
                k3 = (H3 - required_h3 + d - 1) // d
                h3 = H3 - k3 * d
                if h3 < 0:
                    h3 = 0
                if h3 >= h2:
                    continue
        else:
            k3 = 0
            h3 = H3
        # Check conditions
        if h1 < h2 and h3 < h2:
            if h1 != h3:
                total = k1 + k2 + k3
                if total < min_steps:
                    min_steps = total
            else:
                # Try adding one step to k1
                new_k1 = k1 + 1
                new_h1 = max(0, H1 - new_k1 * d)
                if new_h1 < h2 and new_h1 != h3:
                    total = new_k1 + k2 + k3
                    if total < min_steps:
                        min_steps = total
                else:
                    # Try adding one step to k3
                    new_k3 = k3 + 1
                    new_h3 = max(0, H3 - new_k3 * d)
                    if new_h3 < h2 and new_h3 != h1:
                        total = k1 + k2 + new_k3
                        if total < min_steps:
                            min_steps = total
    # Check k2_max for h2=0
    k2_max = H2 // d
    for k2 in [k2_max, k2_max + 1]:
        h2 = H2 - k2 * d
        if h2 < 0:
            continue
        # Compute k1 for H1 < h2
        if H1 >= h2:
            required_h1 = h2 - 1
            if required_h1 < 0:
                if h2 == 0:
                    continue
                else:
                    k1 = (H1 + d - 1) // d
                    h1 = 0
                    if h1 >= h2:
                        continue
            else:
                k1 = (H1 - required_h1 + d - 1) // d
                h1 = H1 - k1 * d
                if h1 < 0:
                    h1 = 0
                if h1 >= h2:
                    continue
        else:
            k1 = 0
            h1 = H1
        # Compute k3 for H3 < h2
        if H3 >= h2:
            required_h3 = h2 - 1
            if required_h3 < 0:
                if h2 == 0:
                    continue
                else:
                    k3 = (H3 + d - 1) // d
                    h3 = 0
                    if h3 >= h2:
                        continue
            else:
                k3 = (H3 - required_h3 + d - 1) // d
                h3 = H3 - k3 * d
                if h3 < 0:
                    h3 = 0
                if h3 >= h2:
                    continue
        else:
            k3 = 0
            h3 = H3
        # Check conditions
        if h1 < h2 and h3 < h2:
            if h1 != h3:
                total = k1 + k2 + k3
                if total < min_steps:
                    min_steps = total
            else:
                # Try adding one step to k1
                new_k1 = k1 + 1
                new_h1 = max(0, H1 - new_k1 * d)
                if new_h1 < h2 and new_h1 != h3:
                    total = new_k1 + k2 + k3
                    if total < min_steps:
                        min_steps = total
                else:
                    # Try adding one step to k3
                    new_k3 = k3 + 1
                    new_h3 = max(0, H3 - new_k3 * d)
                    if new_h3 < h2 and new_h3 != h1:
                        total = k1 + k2 + new_k3
                        if total < min_steps:
                            min_steps = total
    return min_steps

def compute_case2(d, H1, H2, H3):
    min_steps = float('inf')
    max_k2 = 100
    for k2 in range(0, max_k2 + 1):
        h2 = H2 - k2 * d
        if h2 < 0:
            break
        # H1' and H3' must be > h2
        # Compute max steps allowed for H1 and H3 to be > h2
        # For H1: H1 -k1*d > h2 → k1 < (H1 - h2)/d → k1_max = floor( (H1 - h2 -1)/d )
        # since k1 >=0
        if H1 <= h2:
            continue
        # k1 can be 0, as we want minimal steps
        k1 = 0
        h1 = H1
        if H3 <= h2:
            continue
        k3 = 0
        h3 = H3
        if h1 > h2 and h3 > h2:
            if h1 != h3:
                total = k2
                if total < min_steps:
                    min_steps = total
            else:
                # Need to apply one step to either H1 or H3
                # Try H1
                new_h1 = max(0, h1 - d)
                if new_h1 > h2 and new_h1 != h3:
                    total = k2 + 1
                    if total < min_steps:
                        min_steps = total
                else:
                    # Try H3
                    new_h3 = max(0, h3 - d)
                    if new_h3 > h2 and new_h3 != h1:
                        total = k2 + 1
                        if total < min_steps:
                            min_steps = total
    # Check k2_max for h2=0
    k2_max = H2 // d
    for k2 in [k2_max, k2_max + 1]:
        h2 = H2 - k2 * d
        if h2 < 0:
            continue
        if H1 <= h2 or H3 <= h2:
            continue
        k1 = 0
        h1 = H1
        k3 = 0
        h3 = H3
        if h1 != h3:
            total = k2
            if total < min_steps:
                min_steps = total
        else:
            new_h1 = max(0, h1 - d)
            if new_h1 > h2 and new_h1 != h3:
                total = k2 + 1
                if total < min_steps:
                    min_steps = total
            else:
                new_h3 = max(0, h3 - d)
                if new_h3 > h2 and new_h3 != h1:
                    total = k2 + 1
                    if total < min_steps:
                        min_steps = total
    return min_steps

def main():
    d = int(sys.stdin.readline())
    H = [int(sys.stdin.readline()) for _ in range(3)]
    H1, H2, H3 = H[0], H[1], H[2]
    case1 = compute_case1(d, H1, H2, H3)
    case2 = compute_case2(d, H1, H2, H3)
    min_total = min(case1, case2)
    if min_total == float('inf'):
        print(-1)
    else:
        print(min_total)

if __name__ == '__main__':
    main()