import pandas as pd
 
dados = { 
	"Código": [1623,5124,4785,5251,1578,9684,5187, 111, 222, 333, 444, 555 ],
	"Dimensões":["10 15 7", "15 7 8", "20 15 8", 
				"50 70 22", "c10 l20", "50 10 2",
				"75 20 10", "10 cl20", "1c0 l20", "111 212", "111 22 33", "11 22 33 44"],
}
 
# Criar o DataFrame
df = pd.DataFrame( dados )
 
df = df[ ~df['Dimensões'].str.contains(r'[A-Za-z]') &\
     (df['Dimensões'].str.count(' ') == 2) ]
 
print(df)
 
 

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