Replacing if else statement with any design pattern or better approach

This code doesn't look clean and this if condition can grow

public int VisitMonth(int months) { int visit = 0;

        if (months <= 1)
        {
            visit = 1;
        }
        else if (months <= 2)
        {
            visit = 2;
        }
        else if (months <= 4)
        {
            visit = 3;
        }
        else if (months <= 6)
        {
            visit = 4;
        }
        else if (months <= 9)
        {
            visit = 5;
        }
        else if (months <= 12)
        {
            visit = 6;
        }
        else if (months <= 15)
        {
            visit = 7;
        }
        else if (months <= 18)
        {
            visit = 8;
        }
        else if (months <= 24)
        {
            visit = 9;
        }
        else if (months <= 30)
        {
            visit = 10;
        }
        else if (months <= 36)
        {
            visit = 11;
        }
        else if (months <= 48)
        {
            visit = 12;
        }
        else if (months <= 60)
        {
            visit = 13;
        }
        else
        {
            visit = 14;
        }
        return visit;
    }

Is their any better solution to this problem? sadly that function isn't linear so it's not easy to code that in mathematical way