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0_0_6610531_18547.cpp:2:19: math .h: No such file or directory
0_0_6610531_18547.cpp: In function `int euler(int)':
0_0_6610531_18547.cpp:7: error: `sqrt' undeclared (first use this function)
0_0_6610531_18547.cpp:7: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_6610531_18547.cpp: In function `int mod_exp(int, int, int)':
0_0_6610531_18547.cpp:20: error: expected primary-expression before '=' token