1 
P1  Noldbach problem 
Codeforces 
Codeforces Beta Round #17 
2 
P2  Tprimes 
Codeforces 
Codeforces Round #142 (Div. 2) 
3 
P3  Bear and Prime Numbers 
Codeforces 
Codeforces Round #226 (Div. 2) 
4 
P4  Mashmokh and Numbers 
Codeforces 
Codeforces Round #240 (Div. 1) & Codeforces Round #240 (Div. 2) 
5 
P5  Joty and Chocolate 
Codeforces 
Educational Codeforces Round 13 
6 
P6  kFactorization 
Codeforces 
Educational Codeforces Round 19 
7 
P7  kth divisor 
Codeforces 
Educational Codeforces Round 17 
8 
P8  Bash's Big Day 
Codeforces 
Codecraft17 and Codeforces Round #391 (Div. 1 + Div. 2, combined) 
9 
P9  Fedya and Maths 
Codeforces 
Codeforces Round #260 (Div. 2) 
10 
P10  Prime Generator 
SPOJ 

11 
P11  Good Sequences 
Codeforces 
Codeforces Round #162 (Div. 1) & Codeforces Round #162 (Div. 2) 
12 
P12  Irreducable Basic Fractions 
UVA 
