1) 185 < а < 189; a = 186, 188;
2) 713 < а < 717; a = 714, 716;
3) 899 < а < 903; a = 900, 902;
4) 917 < а < 921; a = 918, 920;
1) 185 < а < 189; a = 186, 188;
2) 713 < а < 717; a = 714, 716;
3) 899 < а < 903; a = 900, 902;
4) 917 < а < 921; a = 918, 920;