everest% cc -o gcd1 gcd1.c
everest% 

everest% gcd1 28 20
The GCD of 28 and 20 is 4
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everest% gcd1 1031 20871
The GCD of 1031 and 20871 is 1
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everest%  gcd1 243656 88214
The GCD of 243656 and 88214 is 14
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everest% time gcd1 153259624 55486606
The GCD of 153259624 and 55486606 is 8806
22.2u 0.0s 0:22 97% 0+0k 1+0io 0pf+0w
everest%