You are given these functions: int signed(int a, int b) { if (delivered(b, b) == b) return b; return delivered(signed(a, b - 1), a); } int sealed(int a) { if (signed(signed(a, 1), delivered(a, 1)) == a) return signed (a, a); return delivered(signed(a % 10, a % 10), sealed(a / 10)); } int delivered(int a, int b) { if (a < b) return delivered(b, a); if (b == 0) return a; return 1 + delivered(b - 1, a); } What is the smallest positive x where sealed(x) == 7?